Components of mycobacteria injected in oil/water emulsions into syngeneic tumors growing in the skin of guinea pigs or mice caused the tumors to regress. Animals cured of their tumors were resistant to rechallenge with the same tumor. BIBLIOGRAPHIC REFERENCE: Yarkoni, E., Meltzer, M.S. and Rapp, H.J.: Failure of trehalose-6,6'-dimycolate (P3 or cord factor) to enhance endotoxin lethality in mice. Infect. Immun. 14: 1375-1377, 1976.